The Latest: Prince's sister troubled by death investigation

FILE - This Feb. 8, 2015, file photo shows Prince presenting the award for album of the year at the 57th annual Grammy Awards in Los Angeles. A Minnesota doctor accused of illegally prescribing an opioid painkiller for Prince a week before the musician died from a fentanyl overdose has agreed to pay $30,000 to settle a federal civil violation, according to documents made public Thursday. Prince was 57 when he was found alone and unresponsive in an elevator at his Paisley Park estate on April 21, 2016. An autopsy found he died of an accidental overdose of fentanyl. (Photo by John Shearer/Invision/AP, File)

MINNEAPOLIS (AP) — The Latest on the investigation into the death of Prince, who was found unresponsive on April 21, 2016, after a fentanyl overdose (all times local):

9:15 a.m.

One of Prince's sisters is expressing disappointment about the way the investigation into her brother's death was handled.

Sharon L. Nelson tweeted Friday : "There is so much about Prince's death and this investigation that troubles me and millions of #prince fans around the world."

She questions why authorities didn't immediately collect Prince's computer, files and other records after he died. In another tweet , she references a KSTP-TV article about an investigator who regretted not immediately searching Prince's computer.

She says it "was disappointing and hurtful" and expresses hope that the federal government will do better.

In this image made from surveillance video provided Thursday, April 19, 2018, by the Carver County Sheriff's Office, as part of an investigative file into Prince's death, the superstar, center, enters a clinic of Dr. Michael Todd Schulenberg on April 20, 2016, the day before he was found dead of an accidental fentanyl overdose. The doctor is not facing criminal charges and his attorney says he had no role in Prince's death. (Carver County Sheriff's Office via AP)

Prince was found unresponsive on April 21, 2016, after a fentanyl overdose.

State prosecutors say they haven't determined the source of the fentanyl and no charges will be filed. A federal investigation is now inactive unless new information comes forward.

__

12:30 a.m.

Investigative files released as prosecutors closed their probe into Prince's death show that his closest confidants had grown increasingly worried about his health in the days before he died — and that they tried to get him help.

FILE - In this Feb. 4, 2007 file photo, Prince performs during halftime of the Super Bowl XLI football game in Miami. Minnesota prosecutors are planning an announcement Thursday, April 19, 2018, in their two-year investigation into Prince's death. Prince was found alone and unresponsive in an elevator at his Paisley Park estate on April 21, 2016. An autopsy found he died of an accidental overdose of fentanyl, a synthetic opioid 50 times more powerful than heroin. (AP Photo/Chris O'Meara, File)

But none of his inner circle was able to give investigators the insight they needed to determine where Prince got the fentanyl that killed him.

The files were made public as a county prosecutor announced that no criminal charges would be brought in the case.